Ultrafast Nonlinear Pulse Propagation Dynamics in Metal–Dielectric Periodic Photonic Architectures

Abstract

A promising approach to modulate the metal's dielectric function is achieved by exploiting the nonlinearity of the metal via intense ultrashort laser pulses interaction. Irradiating metal nanostructures with intense ultrafast laser pulse leads to a significant increase in electron temperature compared to that in bulk medium. Hot electron gas undergoes several fast (≈0.5-5 ps) elementary processes such as electron-electron (e-e) and electron-phonon (e-ph) interactions before a new equilibrium with the host lattices is reached. [1,[4][5][6] 1D metal-dielectric (MD) multilayer wavelength-ordered structures have become promising candidates to observe such enhancement in nonlinearities in a fundamental way. [4,5] As a consequence of the Bragg-like resonances, MD photonic multilayer structure is advantageous for accessing the ultrafast nonlinearities at the transmissive photonic minibands in the resonant and nonresonant spectral regimes. [7][8][9][10] These tailor-made photonic metal structures thus lead to the transparency in the visible and infrared regions with more than 50% transparency and show many promising applications in nanosensing, waveguiding, and all-optical switching, exploiting the tunable Kerr nonlinearity of metals.

Photonics of time-varying media

“…255 Artificial ENZ metamaterials exhibiting Dirac cone-like dispersion 256 or multilayered thin films make valuable candidates for time-varying experiments, as they exhibit the favorable ENZ physics, are tunable, and have the potential to exploit other meta-properties, e.g., good coupling to far-field radiation. Subps modulation of the effective permittivity of a multilayered Au∕TiO 2 metamaterial was demonstrated by Rashed et al 257 In parallel, enhancement of nonlinear properties around the ENZ frequency of a multilayered Ag∕SiO 2 258 as well as ultrafast modulation of absorption 259 were reported. This enhancement is explained by the dependence of the effective third-order nonlinear susceptibility on the inverse of the medium's effective index, which reaches a minimum in the vicinity of the multilayered structure's ENZ frequency.…”

Unsymmetrically β-Functionalized π-Extended Porphyrins: Synthesis, Spectral, Electrochemical Redox Properties, and Their Utilization as Efficient Two-Photon Absorbers

“…The detailed experimental setup can be found elsewhere. 108,109 In this experiment, the pump energy has been kept constant at 1 μJ for all of the samples of porphyrins. Both the pump and probe beams have been temporally and spatially overlapped on the sample surface to record the absorption dynamics at different intervals of ultrashort (ps) time scales.…”

Synthesis and the spectral, electrochemical, and nonlinear optical properties of β-dicyanovinyl-appended ‘push–pull’ porphyrins

“…The excited-state dynamics of porphyrin photo-physics was investigated by ultrafast transient absorption spectroscopy (TAS) using an optical pump-probe technique. 76 In TAS measurements, a 400 nm (120 fs, 1 kHz) femtosecond laser pulse (generated though frequency double of 800 nm (120 fs, 1 kHz)) was utilized as a pump beam to excited samples. To monitor the pump-induced modifications and excited-state absorption dynamics, a broadband femtosecond supercontinuum (350-1000 nm) weak probe beam is temporally and spatially overlapped with the pump beam at the sample surface.…”